pin definitions

Pin Definitions R2:

U1V_RXD, U1V_TXD: uart1 txd and rxd pin via logic shifter, 5V compliant
IO0: GPIO 0
VDD: VDD 3.3V from module
RI DTR DCD CTS RTS RXD TXD: Full UART1 pins, extra pins can be used as GPIO or other control functions, please refer to datasheet.
M_K: external MCU control pin, pull high to power on module
U2TXD, U2RXD: uart2 pins, can be used for upgrade firmware.
VUSB, DP, DM, GND: USB debug pins
RST - reset, ADC - analog read pin, V_ext: power supply logic, STAT: status logic, NET: netlight
GND, VIN: Power supply in, support up to 12V.

Pin Soldering Side

on sim card side

on module side